Expansion Alloy
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Expansion Alloy Rod
- Thickness: 0.1mm-50mm
- Width: 50mm-1000mm
- Length: 1000mm-6000mm
- Thickness: 0.02mm-1mm
- Width: 3mm-500mm
- Delivery Forms: Bright shiny surface or anodized surface, supplied in spools or cut-to-length
- Diameter: Ø3mm-Ø100mm
- Length: 100mm-2000mm
- Delivery Forms: Hot rolled, forged or turned
- Diameter: Ø0.03mm-Ø6mm
- Delivery Forms: Bright shiny or anodized, supplied in spools
- Outer Diameter: Ø3mm-Ø200mm
- Wall Thickness: 0.5mm-10mm
- Length: 100mm-6000mm
Chemical Composition
| Elements | 4J29 | 4J36 | |
| Carbon (C) | Not greater than | 0.03 | 0.05 |
| Sulfur (S) | 0.02 | 0.02 | |
| Phosphorus (P) | 0.02 | 0.02 | |
| Manganese (Mn) | ≤0.50 | 0.20-0.60 | |
| Silicon (Si) | ≤0.30 | ≤0.30 | |
| Nickel (Ni) | 28.5-29.5 | 35.0-37.0 | |
| Chromium (Cr) | - | - | |
| Cobalt (Co) | 16.8-17.8 | - | |
| Iron (Fe) | Rest | Rest | |
| Other Elements |
Thermal Expansion Properties
| Alloy Grade | 20°C-100°C | 20°C-300°C | 20°C-500°C |
| 4J36 Invar Alloy | 1.2×10⁻⁶ /°C | 2.5×10⁻⁶ /°C | - |
| 4J29 Kovar Alloy | 4.6×10⁻⁶ /°C | 5.5×10⁻⁶ /°C | 6.2×10⁻⁶ /°C |
Mechanical Properties
| Alloy Grade | 4J36 Invar Alloy | 4J29 Kovar Alloy |
| Density (g/cm³) | 8.1 | 8.2 |
| Tensile Strength (MPa) | 500-600 | 600-700 |
| Yield Strength (MPa) | 250-350 | 300-400 |
| Hardness (HV) | 150-200 | 200-250 |
Electrical Properties
| Alloy Grade | 4J36 Invar Alloy | 4J29 Kovar Alloy |
| Electrical Resistivity (10⁻⁶ Ω·cm) | 80 | 50 |
| Thermal Conductivity (W/m·K) | 10-12 | 16-18 |
Features
- Some expansion alloys, such as Invar alloys, expand almost not at all with temperature changes, while other types can be engineered to have a specific expansion rate.
- These alloys maintain shape and size stability, even in environments with significant temperature fluctuations.
- They typically offer enough strength and toughness, making them suitable for complex structural components.
- They are easy to process with cold and hot working, welding, and other forming techniques.
- Many expansion alloys also exhibit excellent corrosion resistance.
Applications
- Precision instruments and measuring devices: such as balances, microscopes, and laser interferometers
- Electronics and semiconductors: integrated circuit boards, connectors, resistors, etc.
- Aerospace: navigation systems, control systems on aircraft and satellites
- Automotive industry: engine sensors, exhaust system components
- Energy industry: sensitive equipment in nuclear power plants, thermal power stations, such as instrument panels and controllers
- Watchmaking: precision components such as gears and mainsprings in high-end watches
- Lighting industry: metal brackets and connectors in light bulbs and LED lighting fixtures
Packaging